Honda CX 500 Forum banner

1 - 20 of 58 Posts

·
Registered
Joined
·
712 Posts
Discussion Starter #1
I have been able to reprogram the memory chip and alter the Boost limit or remove it all together.




Anybody interested ?
 

·
Registered
Joined
·
254 Posts
Not just yes. HELL YES!
 

·
Registered
Joined
·
2,345 Posts
Pim, this is just great, I have to get up at 4:15 in the morning to catch an early flight and you leave me dreaming about this. Maybe the "grenade" post earlier may help me get to sleep. Count me in. We can talk about the 650 too.
 

·
Registered
Joined
·
37 Posts
I don't understand. On my CX500TC, when the boost is above 1,22 bar, the motor running well. There is only the red turbo light on without ignition or injection switch off. With the turbo controler I can running over 1.3bar and no problème

Somebody can explain me.

Thanks
 

·
Registered
Joined
·
712 Posts
Discussion Starter #7
I don't understand. On my CX500TC, when the boost is above 1,22 bar, the motor running well. There is only the red turbo light on without ignition or injection switch off. With the turbo controler I can running over 1.3bar and no problème

Somebody can explain me.

Thanks


Above 1.5 Bar / 21 Psi the fuel computer will go into limb mode ( Red light ). Which means the computer detects that your P2 sensor output is not correct, it will then discard the P2 sensor and replaces this with a fixed pressure of 0 bar ( 1 bar absolute ). This will result in a large reduction of fuel injected into the engine which ofcourse results into a lot of power lost.
 

·
Registered
Joined
·
712 Posts
Discussion Starter #8
Some comments on removing the Boost Limit.



- The P2 sensors only measure up to aproximate 1.7 Bar / 25 Psi above this pressure the output voltage does not rise anymore, this means that the boost limit can be changed up to 1.7 Bar / 25 Psi, above this the boost limit is practicly removed.



- I did some testing and with full throttle / 25 Psi boost / 10.000 RPM the injection time goes to 100%



So now how it can be done :



Open your Fuel Injector Unit and remove the memory chip :







Get a chip tuning kit consiting of an Eprom chip and a Chip Socket







Solder the Chip Socket in place and add the Eprom :







Plug and Play
 

·
Registered
Joined
·
37 Posts
OK, thanks for the answer.

I 'm not sure that the cluch like that. When I adjusted the boost controler, the pressure go above 1.6 bar (22.2psi) and my cluch took a bad way, I have to change it now. It have 5000km (3000 milles). Can be a bad mark



Do you know the RPM of turbo at these pressures?
 

·
Registered
Joined
·
815 Posts
When you say 100% at 25 psi...does that mean in stock form at ~19 psi, the fuel system isn't at 100% and the map continues to compensate up to 25 psi?

Or is it at 100% in stock and modified form when maxed out? If so, you're not getting a lean condition?



Do you have the code for download somewhere?
 

·
Registered
Joined
·
37 Posts
I have a part of your question.

I have a lamda sensor on my exhaust system with a lambda controler, and a boost controler. With the boost controler off, the lambda is a little more than 1 for 4000/5000 RPM with a boost pressure around 0.5 bar (7.3 PSI). When the boost controler is on and with the same RPM, there is a pressure around 0.7 bar (10.1PSI) and a lambda value is down of 1.

At the max pressure it's the same thing, the lambda go down more there is pressure. I try it with a max pressure of 1.6bar (23.2PSI)

So more there is pressure, more there is fuel injected. After like said Pim, there is the limits of the the system, computer and pressure sensor.
 

·
Registered
Joined
·
37 Posts
PIM, do you have the values pressure/tension for the sensor P2 ?

If yes, can you make us a table with these values?

Thanks
 

·
Registered
Joined
·
712 Posts
Discussion Starter #13
PIM, do you have the values pressure/tension for the sensor P2 ?

If yes, can you make us a table with these values?

Thanks


I placed this table before but here the table with the pressure versus the Turbo sensor outputs :







Further with my test setup :







I run some graphs with injection time versus engine rpm :















As you can see at 27 Psi boost / 10000 RPM the fuel injectors stay open 90% of the time, not perfect but acceptable.




Running 27 Psi boost and run it up to 11000 RPM the fuel injectors stay open and that is not good.
 

·
Registered
Joined
·
1,521 Posts
At 100% duty cycle, the fuel injectors are wide open- maximum fuel flow possible. Holding them wide open may burn them up in short time, maybe 1-2 minutes or so... possibly a bit longer if the fuel flowing through them can sufficiently cool them. However, at some range above 90% and less than 100% duty-cycle, which actually depends on the characteristics of the injector- how fast the coil field collapses, pintle inertia, et cetera (low-impedance injectors usually operate quicker than high-impedance and can tolerate higher duty-cycles), the time it takes the injector to cycle from opened to closed and back open is greater than the time power is not applied to the injectors thus the pintles could be 'floating' somewhere between open and closed. This range of duty-cycles could cause the mixture to fluctuate significantly since the injector is neither fully opened or closed and is probably the reason the ECU faults and limps when boost pressure exceeds ~21 PSI.



I can see several ways to work with the boost/fuel cut eliminated:

1) Reprogram the ECU to defeat the fuel cut and piggyback fuel controller to add fuel when the stock injectors are saturated. Note this does not avoid the problem with the stock injectors' pintles "floating" and if the piggyback does not have it's own MAP sensor for higher boost, it does not accommodate boost above 25 psi as that's when the P2 sensor is saturated and no longer producing any useful information for the ECU.

2) Reprogram the ECU to defeat the fuel cut, larger fuel injectors and reprogram the ECU to accommodate the higher flow of the injectors. Again, though, this does not accommodate boost above 25 psi since P2 saturates above 25 psi and therefore the ECU cannot calculate fuel above that point. That's not to say that a sensor with a comparable output but extended pressure range couldn't be substituted for P2, but such a sensor would have a different "curve" so the ECU would need reprogrammed for that.

3) Limit the P2 sensor output to a level it reads prior to entering limp mode which for argument's sake I'll say 19 PSI: this should defeat the over-boost cut without altering the ECU. Then use a piggyback / add-on fuel controller, MAP sensor and injector for additional fuel above what the ECU is injecting. Where to locate this "third" injector and bringing fuel to it could be a problem.

4) Limit the P2 sensor output as above, replace the stock injectors with larger injectors and use an add-on fuel controller and MAP sensor to modify the stock ECU's signals to the injectors.

5) Eliminate the factory ECU and use an aftermarket controller with larger injectors and such as required.
 

·
Registered
Joined
·
1,206 Posts
Overall I like the thinking of getting some more useful speed,



but there seems to be inherent danger of popping a valve and/or something mechanical going "bang" real quick..



forgive my simple thoughts on all of your well thought out processes.....waiting for more
 

·
Registered
Joined
·
712 Posts
Discussion Starter #16
5) Eliminate the factory ECU and use an aftermarket controller with larger injectors and such as required.


Oke I will do stage 1 - 90 HP ( remove Boost limit ) and stage 2 - 110 HP ( larger injectors with reprogrammed ECU )



And you do stage 3 - 125HP+ , all new ECU
 

·
Registered
Joined
·
1,521 Posts
Oke I will do stage 1 - 90 HP ( remove Boost limit ) and stage 2 - 110 HP ( larger injectors with reprogrammed ECU )



And you do stage 3 - 125HP+ , all new ECU
Sounds like a plan.
 

·
Registered
Joined
·
2,345 Posts
Okay Pim, now that you have split the atom, it sounds like we need to plan a group purchase on pistons if everyone is going to be dialing up the boost.
 

·
Registered
Joined
·
1,521 Posts
Okay Pim, now that you have split the atom, it sounds like we need to plan a group purchase on pistons if everyone is going to be dialing up the boost.


Maybe it would be beneficial to put a TC on a dyno and exhaust sniffer to measure AFR at full boost & load in top gear to get an idea of what can be done. If it's around 10:1, there may be some room to run a bit leaner but how much would depend on the actual cylinder / combustion temperatures and anything above 11:1 would be suspect without proof the injector pintles aren't going to float and lean it out with duty-cycles >90 and <100. Without the ability to affect ignition timing, the rich mixture is the only thing keeping the pistons cool.



The only viable options may be defeating the boost fuel cut and using larger injectors in conjunction with a reprogrammed ECU or using aftermarket piggyback or full ECUs.



Throwing an intercooler in there may be even more problematic since there's no way for the factory ECU to determine how much air really is entering the engine due to the location of the air-temp sensor.
 

·
Registered
Joined
·
254 Posts
Meth injection will save the pistons too
 
1 - 20 of 58 Posts
Top